[meteorite-list] Show me the Shock

[Robert Verish]

https://www.space.com/boomerang-meteorite-left-earth-and-returned

A dark reddish-brown stone, picked up from the Sahara desert in Morocco a
few years ago, appears to be an Earth rock that was flung into space where 
it stayed for thousands of years before returning home ? surprisingly intact. 

If scientists are right about this, the rock will officially be named the 
first meteorite to boomerang from Earth. [Not for certain!]

The discovery team's work was *presented*
( https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi/Paper/20218 )
last week at an international geochemistry conference and has not yet been
published in a peer-reviewed journal.

"I think there is no doubt that this is a meteorite," said Frank Brenker, a
geologist at the Goethe University Frankfurt in Germany, who was not
involved with the new study. "It is just a matter of debate if it is really 
from Earth."  [But, still could be the other way around.]

Early diagnostic tests show the unusual stone features the same chemical
composition as volcanic rocks on Earth. Interestingly, however, a few of
its elements seem to have been altered into lighter forms of themselves.
These lighter versions are known to occur only upon interacting with
energetic *cosmic rays* ( https://www.space.com/32644-cosmic-rays.html ) 
in space, which provided one of two key pieces of evidence 
declaring the rock's trip beyond Earth, geologists say.

Other pending measurements include unambiguous data about how much shock 
from the original impact the stone absorbed. This unique signature can be detected 
in the permanently altered microstructures of the mineral crystals forming the rock. 
Estimating the meteorite's shock levels is "something that can be checked or done 
in one hour or so max, using naked eyes," Ferrière said, "thus, not costly and a 
very important observation in this case."  

( https://cdn.mos.cms.futurecdn.net/uh7CnCZNh4MNnFY78yR2ke.jpg )